Method of preparing halogen-oxygen compounds by electrolysis.



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' Specification of Letters Patent. Patented Sept. 10,1912. .pplic'ation fi ed April 8, 1911. Serial in). 619,636. 7

' Be'it "known that I, MATHIAS PER, doctor of philosophy, subject of the Emperor of Germany, residin at Schlachtense'e, .near Berlin, Prussia, ermany, have invented a new and useful Improvementin the Method of I eparing Halngen-Oxygen Compounds by Electrolysis, of which the following is a full, clear, and exact description. Y

During the electr( )lysisof the alkalis and alkaline earths for the preparation of the corresponding halogen-oxygen compounds it "has been found tobe of advantage in order to obtain high yields of material on the currentnsed to add'to the electrolyte a chlorid or a metal which, is precipitated by means of alkali from the salt solutions of same in the form of a'n-oxid or hydroxid. In order to insure the efliciency ofthese additions, the presence of chromate gwas heretofore cons ered necessary. .I have discovered that the technical chlorid (bf cerium :forms an exeeptionfto this rule to such an extent that by means of the addition of same to the electrol e high yields of 1 aterial on the current are obtained wilbfout the addition of chromate. This specifi property, to prevent the reduction of hypohalogen acids, is also a propertyof othercom ounds of rare earth metals, but the use 0 cerium,chlorid was feund to be of special advantage.

All the compounds of the rare earth metals with which I have experimented separate at the cathodeupon electrolysis in an insol ble form which adheres, forming a visible, effective diaphragm. That part which is not consumed for the formation of a cover for l1e.e1ctrode is precipitated as an insoluble The electrolyte itself remains entirely free from impurities and entirely clear.

In theliterature of the art, substances are repeatedlymentionedwhich, it is claimed, render possible arf increase in the yield of chlorate in the same manner as the rare earth metals, e. without the addition of chromate. For instance, vanadium comorder to increase the yield, but it was found that the addition of vanadium compounds either does not increase the chlorate yield at all, orthat this yield is unfavorably influenced by this addition. The vanadium compounds separate principally at the anode in thick crusts, which during continuous operatlon are bound to unfavorably influence the operation. The chlorate solutions, furthermore, are strongly colored. 7

Still more unfavorable results are obtained when operating with the addition of iron and copper compounds. In this instance also, as shown in the attached comparative tables, the yield of material obtained on the current is not increased but rather reduced. The examples cited below, on the other hand, prove that by means of an addition, as claimed in the present specification, of salts of the metals of the rare earths with the acid electrolytes, highly satisfactory technical results are obtained.

- Examples: 1800 com. of a 28% sodium chlorid solution to which 4 grams of cerium chlorid had been added were subjected to a electrolysis between graphite and platinum electrodes, While HCl gas was introduced. The temperature of the bath was about C. The experiments were continued to 1300 ampere hours and more. The losses during theelectrolysis were determined by means of collecting and analyzing the gases developed.

TABLE 1.Per cent. yield of sodium chlorate on current used.

With cerium Withchromate Without any Ex nment. chlorid andhyi and hydrope drochloricacid. chloric acid. I

TABLE 2.-Pes

cent. yield of hii'dium chlorate om puwant used.-

- Addition of rare metals. II. Addition of IIIJAdditio n 0! IV. Addition of 1 Time 111 am- I. In weak 801d C 2 4 i Y M m ch-mrm num ehlond umchlond per per hwr. liter. 20 62.8 53. 5 56. 1 i 59.9 67.0 66.5 65. 300 54.8 56. 4 41. 7 28. 84. 0 80. 0 78. 430 54. 6 54.4 45. 9 27.6 87. 0 81.0 77.5 900 52.6 55.0 86.0 82. 0 80. 0 1,242 86.5 83.3 81.3

The quantities of chlorids specified in the ebove tabulation are those which, in each instance, give the maximum yield; Having now fully described my invention,

what I claim and desire'to protect 'by: Let

ters Potent. is:

..;The method of preparinghalogen-oxygen compounds of the jalkalis and alkaline earthsby electrolysis which consists in add- HENRY HASPER,

Wonnmnm HAUPT. 

